An improved cubic law for shale fracture considering the effect of loading path

Massive multi-stage hydraulic fracturing to form one large-scale stimulated reservoir volume (SRV) with a complex fracture network is a key technique in shale gas development. A natural fracture system may contribute significantly to gas production. Fracture apertures are the key parameter for determining flow characteristics of jointed rock media and changes due to loading and unloading behaviour. In this study, a hydraulic aperture model was proposed to describe aperture variation in a complex loading path with a parabolic function. A numerical study of the hydro-mechanical model was conducted to determine the influences of loading path and nonlinear effects on fluid flow at field scale. In this specific simulation, the total flow volume considering the influence of loading path only decreased by 14%, and considering the influence of loading path decreased by 28%, meanwhile influence of two factors resulted in a 39% reduction of the total flow volume. [Received: July 25, 2018; Accepted: July 3, 2019]